The Loughor viaduct replacement scheme is part of a £40m upgrade to rail infrastructure between Swansea and Gowerton,
Carillion will design and build the new viaduct, carrying two tracks along the current alignment.
Work will start this spring. Subject to planning approval and listed building consent, Network Rail is proposing to keep the existing natural stone abutments and some of the Grade II listed trestles and erect a small section of the old Loughor viaduct on the West shore as part of its conservation efforts.
Work will start in the autumn on later stages of the overall project, including upgrading work on bridges at Rhosog, River Lliw and Gypsy Cross.
The schemeis jointly funded by Network Rail and the Welsh government.
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